Mechanically controllable valve drives of the above type are well known from the state of the art in the field of internal combustion engines. They have in particular the purpose, by use of the valve lift height and the duration of the opened state of the valve, and thus by use of the filling degree of the cylinders in the internal combustion engine, to adapt the combustion process to the respective load requirements and, correspondingly, to achieve a maximally efficient and thus also a low-pollutant combustion. Apart from this, it is known that in certain load ranges, especially in the part-load range, a certain number of cylinders can be completely switched off, for example, in a four-cylinder engine, in order to run the engine merely with two cylinders. For this purpose, the gas exchange valve is operated in the zero-lift range, which at the same time means that the valve acceleration in this range is zero. This zero-lift range is followed by an adjustment range which at a certain turning angle point will effect a maximum lift of the gas exchange valve. The integral under the whole valve-lift curve will thus determine the filling volume in a gas-exchange inlet valve and, respectively, the exhaust-gas discharge volume in a gas-exchange outlet valve.
With respect to the filling volume, a valve drive of the above design is thus dependent on the maximum obtainable valve lift. In this regard, particularly large valve lifts have the disadvantage that they require a large constructional space to allow for adjustability, that they entail a danger of piston collision and, respectively, that there will be generated higher frictional forces during an opening process against the return spring of the gas exchange valve.